When a dental implant is implanted into the jaw bone of a patient, it is often difficult to determine whether sufficient bonding has occurred between the dental implant and the jaw bone. Currently, taking an x-ray of a patient's jaw and inspecting the x-ray for structural integrity between the dental implant and the jaw bone is a common method for determining whether a dental implant is properly bonded to the jaw bone. However, in cases where the progress of a dental implant must be followed over a period of time, the use of x-rays is undesirable due to medical considerations caused by the cumulative effect of multiple exposures to x-rays.
A number of attempts have been made to provide an apparatus for determining the mobility of a dental implant or tooth which does not require x-rays to be taken. One such attempt is found in U.S. Pat. No. 3,094,115, which discloses a tooth mobility indicator. In use, the patient sits in a dental chair with his head resting upon an oscillating element which vibrates the patient's teeth. A hand-held probe containing an accelerometer is placed upon a tooth to measure the amplitude of the vibrating tooth. The probe registers the departure of the amplitude and frequency of the signal received by the accelerometer from the input signal of the oscillating element. This method of measurement is subject to error due to variability in the placement of the oscillating element as well as distortion of the data measured through the patient's head and by the probe resonances themselves.
Another attempt is found in U.S. Pat. No. 4,470,810 which discloses a hand held probe for applying a motion to a tooth and measuring the displacement of the tooth from which the displacement rate of the tooth can be found. Since the displacement of a tooth is usually less than 1 millimeter, an instrument measuring such small displacements must be extremely accurate. However, displacement measurements measured with this probe use the probe itself as a reference point. As a result, the displacement measurements are subject to a high degree of error caused by variations in the angle at which the probe is held as well as the force at which the probe is pressed against the tooth.
A similar attempt is found in U.S. Pat. No. 4,881,552 which discloses a tooth stability monitor having a hand-held probe for assessing the rigidity of a tooth. The probe measures the displacement of the tooth and the resulting force applied to the tooth. This instrument is subject to the same errors experienced by the probe in U.S. Pat. No. 4,470,810.
Still another attempt is found in U.S. Pat. No. 4,482,324 which discloses a hand-held probe for determining the degree of looseness of a tooth. The instrument includes a ram which is disposed at a right angle with respect to the handle of the instrument. The ram is accelerated to a specific velocity and after impact against a tooth, the ram is repelled in a direction towards the initial position. The time required for the ram to return is a direct indicator of the degree of tooth mobility. This method is also subject to error due to variations in the manner which the probe is held relative to the tooth.